Originally Posted by TWIN RIG
Anybody got any proof of it doing 90+ ? I've seen a lightweight Phantom 20 with a 300xs fitted that struggled to do 83 in the hands of a very experienced driver .
Well Ive been in the boat doing those speeds....
Mutz Nuts is a light built P20, Engine is a 3.0L merc which started out as a 300 promax, and after the following mods it makes 355hp and 370ft pounds of torque!
MAD EFI High compression Heads
MAD EFI Tripple intake
MAD EFI Short Shaft Midsection
MAD EFI Exhaust tuner
MAD EFI Remapped Fuel ECU
MAD EFI Fuel Adjuster (Fuelling adjustable from drivers seat)
MAD EFI Remapped Ignition ECU
MAD EFI Timing bracket (adjustable timing)
MAD EFI Quad gearbox oil seal conversion
Simon Motorsports Drystacked exhaust
EGT's, CHT & RPMS all monitered by quad Digatrion
Engine went on a diet which included the following
All Standard fuel system removed including canister, both intergrated fuel pumps, both oil reservoir's
Light weight drive shaft (1/4 the weight of the original)
The engine modification all reduced weight significantly aswell such as the change to the MAD EFI intake which saved 11lbs the exhaust tuner was 8lbs lighter, the 5" shorter mid section was significantly lighter
Overall dry weight is just over 180kgs which is about the same as a 20" offshore XR2!
I have driven Mutz @ 85mph (gps) and jabbing the throttle even at that speed the boat still lunges forward.
The shortshaft & belly petrol tank which were added to lower center of gravity worked so well and now the mutz is VERY stable and at those speeds.
The boat handles a thousand times better than when it had the standard 300 promax with a long shaft so I can completely see where your coming from, however this really cant be described as a 300 promax anymore
7k rpm pushes the boat to mid 90's with 10% prop slip
.....7.5K theoretical speed = 102mph with 10% slip
The limiter is 7500 rpm, gear ratio is 1.615:1 & prop is 26" if you want to confirm the figures. (Wayne Taylor, Owner of MAD EFI suggested setting limiter @ 8k however we decided 7.5 to prolong the life of the engine.
With the amount of torque that this motor makes combined with a light setup I dont think it would struggle to hit the limiter.